
#include <iostream>
#define _USE_MATH_DEFINES 
#include <math.h>
using namespace std;

void print_beta( int km, double tm, int kn, double tn, double& sum) {
	double pi_value = M_PI;
	double ret = (2 * pi_value * (kn * tm - km * tn)) /(tn * tn * tm - tm * tm * tn);
	cout << ret << endl;
	sum += ret;
	return;
}


int main() {
	int kn;
	double tm;
	int km;
	double tn;
	double sum;
	for (int i = 0; i < 4; i++) {
		cin >> km >> tm >> kn >> tn;
		print_beta(km,tm,kn,tn,sum);
	}
	sum /= 4;
	cout << "average: " << sum << endl;
	return 0;
}